Bilzerian's lawyer, Tom Goldstein, fired off a bombastic, and hysterical, letter to the lawyer for Janice Griffith -- who says she broke her foot when Bilzerian threw her off a roof, and into a pool during a photo shoot.

In the letter, Bilzerian and Goldstein claim Griffith clearly gave permission to do the stunt, and therefore has no basis to sue -- or as they put it ... "Like your client, the facts of the claim won't, quite, fly."

The letter is dripping with sarcasm, a ton of barbs about her porn career (you should seriously read the whole thing) -- and a detailed description of what will happen if Griffith takes legal action:

"Your client should just box up almost every last bit of her property (please exclude all videos and photographs as well as the seemingly inevitable small yappy dog) and drop it off with you in safe-keep for Mr. Bilzerian. After he receives the judgement in his favor, he will have it all delivered to him. Then he will probably blow it up with a mortar in the desert."